Label and method of making

ABSTRACT

A method of providing an image on a media having a image-receiving layer and a protective overlayer, comprising the steps of providing an image on said image-receiving and providing machine-readable indicia on said protective overlayer by varying the temperature of a thermal head used to apply said protective overlayer.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a Divisional of U.S. application Ser. No. 10/310,519,filed Dec. 5, 2002 entitled IMPROVED LABEL AND METHOD OF MAKING byLoretta E. Allen, Robert C. Bryant, William H. Simpson, David L. Pattonand Peter A. Frosig, which is a Continuation-in-Part of application Ser.No. 10/213,991 filed Aug. 7, 2002, entitled THERMAL DYE TRANSFERPRINTBEARING PATTERNED OVERLAYER AND PROCESS FOR MAKING SAME by William H.Simpson, David Andrew Johnson, Cobb S. Goff and David Edward Coons.

FIELD OF THE INVENTION

[0002] The invention relates to a thermal dye transfer print comprisinga protective overlayer including indicia written in the protectiveoverlayer.

BACKGROUND OF THE INVENTION

[0003] U.S. Pat. No. 6,092,942 (Koichi et al.) includes a thermal dyedonor element composed of a yellow, magenta and cyan dye patch plus aprotective overlayer which is applied to the receiver layer containingthe printed image by means of a thermal print head. The protective layeris applied by using an image plane as a mask as opposed to a uniformapplication of energy down the page. The protective layer image isdesigned to have low and high energy areas arranged in a pattern toproduce corresponding regions of density in the transferred protectivelayer. The final pattern in the transferred protective overlayerrepresents indicia that can be interpreted by detecting the variationsin the thickness of the protective layer either mechanically oroptically.

[0004] Traditional bar codes formed using a combination of the cyan,magenta and yellow dyes in a thermal printer produce a relatively poormachine-readable code because of the lack of carbon black in these dyes.Carbon black, and similar absorbing materials, enhance the absorption ofthe near-infrared and red wavelengths used by many handheld andpoint-of-sale scanners to read bar codes. Typically, for a bar code tobe read reliably, it is preferred that the dyes used in the printing ofthe bar code symbol absorb light in the near infrared and redwavelengths.

[0005] Today, more and more information is required on a product label.More information requires a larger area onto which to print theinformation, which translates into bigger labels. Bigger labels may notbe acceptable for many products, particularly small items such as beautyand pharmaceutical products. Thus, there is a need to provide Economy oflabel by providing more information often on smaller labels that arehuman and/or machine-readable.

[0006] The present invention provides a thermal dye transfer printbearing a protective overlayer wherein the overlayer is selectivelyapplied in such a manner so as to represent indicia. The presentinvention also provides a thermal dye transfer print wherein at least aportion of the indicia provided in the protective overlayer is identicalin content and location to indicia provided in the image layer so as toenhance the readability of the indicia. The present invention alsoprovides a thermal dye transfer print wherein at least a portion of theindicia provided in the protective overlayer is different to indiciaprovided in the image layer. The invention also provides a process formaking such prints as well as a method of reading the indicia.

[0007] The present invention also allows the providing of moreinformation on a label than traditionally printing human readableindicia on an image layer. In particular, this is accomplished bythermally printing machine-readable indicia in a protective overlayer.The machine-readable indicia located in the protective overlayer can belocated in the same area of the label as human-readable indicia. Forinstance, product information, information that the consumer isinterested in, is printed on the image layer. Bar code information orother product tracking information, information that the consumer is notinterested in, is printed in the protective overlayer. Therefore, a moreaesthetically pleasing or attractive label can be manufacturedcomprising a print with a thermally transferred protective overlayercontaining machine-readable indicia.

[0008] In addition, a method of enhancing the machine readability of abar code printed with cyan, magenta and yellow dye is disclosed.

SUMMARY OF THE INVENTION

[0009] In accordance with one aspect of the present invention there isprovided a method of providing an image on a thermal media having aimage-receiving layer and a protective overlayer, comprising the stepsof:

[0010] a) providing an image on the image-receiving layer using athermal head, and;

[0011] b) providing machine-readable indicia on the protective overlayerby varying the temperature of the thermal head used to apply theprotective overlayer.

[0012] In accordance with another aspect of the present invention thereis provided a method of providing an image on a media having aimage-receiving layer and a protective overlayer, comprising the stepsof:

[0013] a) providing an image on the image-receiving layer;

[0014] b) providing machine-readable indicia on the protective overlayerby varying the temperature of a thermal head used to apply theprotective overlayer.

[0015] In accordance with yet another aspect of the present inventionthere is provided a method of providing an image on a thermal mediahaving a image-receiving layer and a protective overlayer, comprisingthe steps of:

[0016] a) providing an image on the image-receiving layer using athermal head, and;

[0017] b) providing indicia on the protective overlayer by varying thetemperature of the thermal head used to apply the protective overlayer.

[0018] In accordance with still another aspect of the present inventionthere is provided a method of providing an image on a thermal mediahaving a image-receiving layer and an protective overlayer, comprisingthe steps of:

[0019] a) providing machine-readable indicia on the protective overlayerby varying the temperature of the thermal head used to apply theprotective overlayer.

[0020] In accordance with another aspect of the present invention thereis provided a method of providing an image on a thermal media having anprotective overlayer, comprising the steps of:

[0021] a) providing machine-readable indicia on the protective overlayerby varying the temperature of the thermal head used to apply theprotective overlayer.

[0022] In accordance with yet still another aspect of the presentinvention there is provided a method of providing a machine-readableindicia on a media having a protective overlayer comprising the stepsof:

[0023] a) providing a 1^(st) machine-readable indicia in an image layeron the media;

[0024] b) providing a 2^(nd) machine-readable indicia in a protectiveoverlayer that is identical in content to, and in register with the1^(st) machine-readable indicia in the image layer.

[0025] In accordance with still another aspect of the present inventionthere is provided a method of providing indicia on a media having aprotective overlayer comprising the steps of:

[0026] a) providing a 1^(st) machine-readable indicia in an image layeron the media;

[0027] b) providing a 2^(nd) machine-readable indicia in a protectiveoverlayer that is identical in content to, and in register with the1^(st) machine-readable indicia in the image layer.

[0028] In accordance with yet another aspect of the present inventionthere is provided a media comprising:

[0029] a) an image-receiving layer on which an image may be formed, and;

[0030] b) a protective overlayer provided over the image-receivinglayer, the protective overlayer having machine-readable indicia formedthereon.

[0031] In accordance with still another aspect of the present inventionthere is provided a media comprising:

[0032] a) an image-receiving layer on which an image may be formed usinga thermal head, and

[0033] b) a protective overlayer provided over the image-receivinglayer, the protective overlayer having machine-readable indicia formedthereon.

[0034] In accordance with another aspect of the present invention thereis provided a media comprising:

[0035] a) a 1^(st) machine-readable indicia in an image layer on themedia;

[0036] b) a 2^(nd) machine-readable indicia in a protective overlayerthat is identical in content to, and in register with the 1^(st)machine-readable indicia in the image layer.

[0037] In accordance with still yet another aspect of the presentinvention there is provided a label comprising:

[0038] a) a image-receiving layer on which an image may be formed usinga thermal head, and

[0039] b) a protective overlayer provided over the image-receivinglayer, the protective overlayer having machine-readable indicia formedthereon.

[0040] In accordance with another aspect of the present invention thereis provided a computer program that when programmed in a computer causesthe computer to provide the steps of:

[0041] a) forming a 1^(st) machine-readable indicia in an image layer ona media;

[0042] b) forming a 2^(nd) machine-readable indicia in a protectiveoverlayer that is identical in content to, and in register with the1^(st) machine-readable indicia.

[0043] In accordance with yet another aspect of the present inventionthere is provided a method of reading a media having indicia formed in aprotective overlayer, the indicia having a physical topography thatrepresents a machine-readable code comprising the steps of:

[0044] a) reading the physical topography of the indicia by a machine soas to obtain information encoded therein, and

[0045] b) interpreting the encoded information so as to obtain theinformation.

[0046] These and other aspects, objects, features and advantages of thepresent invention will be more clearly understood and appreciated from areview of the following detailed description of the preferredembodiments and appended claims and by reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In the detailed description of the preferred embodiments of theinvention presented below, reference is made to the accompanyingdrawings in which:

[0048] FIGS. 1-3 shows various embodiments of a print in the process ofhaving the protective overlayer applied;

[0049]FIG. 4 is an exploded view of a label showing the image layerseparate from the protective overlayer;

[0050]FIG. 5 is a plan view of a label having machine-readable indiciaimbedded the protective overlayer, and located on a product;

[0051]FIG. 6A is a graph showing the results of a topographic test done(Gould Microtopographer stylus instrument);

[0052]FIG. 6B is a single trace of the graph of FIG. 6A;

[0053]FIG. 7A is a graph showing the results of a topographic test done(Zygo);

[0054]FIG. 7B is an elevation view of the graph of FIG. 7A;

[0055]FIG. 8A represents a method of reading the encoded overcoat bymeans of direct illumination;

[0056]FIG. 8B represents a method of reading the overcoat by means ofdirect illumination in conjunction with a polarization analyzer;

[0057]FIG. 9 is an exploded view of a label showing the image layer andprotective layer having the identical image; and

[0058] FIGS. 10-13 shows various embodiments of a print in the processof having the protective overlayer applied.

DETAILED DESCRIPTION OF THE INVENTION

[0059] The invention is summarized above. It encompasses a thermal dyetransfer print bearing a protective overlayer, wherein the protectiveoverlayer comprises information-bearing indicia, especially indicia thatis machine-readable, a process for making the print, and a method ofreading the information-bearing indicia.

[0060] The print of the invention includes overcoat arrangements whereinthe protective overlayer additionally comprises an IR absorbing dye orwhere the thickness of the protective overlayer varies.

[0061] The process for forming the protective overlayer on a thermal dyetransfer print comprises:

[0062] 1) applying to the print a solid sheet comprising a polymericbinder or layers of polymeric material; and

[0063] 2) applying heat selectively to the surface of the protectiveoverlayer sheet.

[0064] Suitably, in the process of the invention, the heat is appliedvia a thermal print head, especially one where the thermal print head isvariable as to which pixels are energized and/or the extent to whichpixels are energized. Alternatively, the protective overlayer containsan IR dye and the heat is applied via selective application of a laserbeam.

[0065] Any dye can be used in the dye layer of the dye-donor element ofthe invention provided it is transferable to the image-receiving layerby the action of heat. Especially good results have been obtained withsublimable dyes. Examples of sublimable dyes include anthraquinone dyes,e.g., Sumikaron Violet RS® (Sumitomo Chemical Co., Ltd.), Dianix FastViolet 3R FS® (Mitsubishi Chemical Industries, Ltd.), and Kayalon PolyolBrilliant Blue N BGM® and KST Black 146® (Nippon Kayaku Co., Ltd.); azodyes such as Kayalon Polyol Brilliant Blue BM®, Kayalon Polyol Dark Blue2BM®, and KST Black KR® (Nippon Kayaku Co., Ltd.), Sumikaron Diazo Black5G® (Sumitomo Chemical Co., Ltd.), and Miktazol Black 5GH® (MitsuiToatsu Chemicals, Inc.); direct dyes such as Direct Dark Green B®(Mitsubishi Chemical Industries, Ltd.) and Direct Brown M® and DirectFast Black D® (Nippon Kayaku Co. Ltd.); acid dyes such as KayanolMilling Cyanine 5R® (Nippon Kayaku Co. Ltd.); basic dyes such asSumiacryl Blue 6G® (Sumitomo Chemical Co., Ltd.), and Aizen MalachiteGreen® (Hodogaya Chemical Co., Ltd.); or any of the dyes disclosed inU.S. Pat. No. 4,541,830, the disclosure of which is hereby incorporatedby reference. The above dyes may be employed singly or in combination toobtain a monochrome. The dyes may be used at coverage of from about 0.05to about 1 g/m² and are preferably hydrophobic.

[0066] A dye-barrier layer may be employed in the dye-donor elements ofthe invention to improve the density of the transferred dye. Suchdye-barrier layer materials include hydrophilic materials such as thosedescribed and claimed in U.S. Pat. No. 4,716,144.

[0067] The dye layers and protection layer of the dye-donor element maybe coated on the support or printed thereon by a printing technique suchas a gravure process.

[0068] A slipping layer may be used on the backside of the dye-donorelement of the invention to prevent the printing head from sticking tothe dye-donor element. Such a slipping layer would comprise either asolid or liquid lubricating material or mixtures thereof, with orwithout a polymeric binder or a surface-active agent. Preferredlubricating materials include oils or semi-crystalline organic solidsthat melt below 100° C. such as poly(vinyl stearate), beeswax,perfluorinated alkyl ester polyethers, poly-caprolactone, silicone oil,poly(tetrafluoroethylene), carbowax, poly(ethylene glycols), or any ofthose materials disclosed in U.S. Pat. Nos. 4,717,711; 4,717,712;4,737,485; and 4,738,950. Suitable polymeric binders for the slippinglayer include poly(vinyl alcohol-co-butyral), poly(vinylalcohol-co-acetal), polystyrene, poly(vinyl acetate), cellulose acetatebutyrate, cellulose acetate propionate, cellulose acetate or ethylcellulose.

[0069] The amount of the lubricating material to be used in the slippinglayer depends largely on the type of lubricating material, but isgenerally in the range of about 0.001 to about 2 g/m². If a polymericbinder is employed, the lubricating material is present in the range of0.05 to 50 weight %, preferably 0.5 to 40 weight %, of the polymericbinder employed.

[0070] Any material can be used as the support for the dye-donor elementof the invention provided it is dimensionally stable and can withstandthe heat of the thermal printing heads. Such materials includepolyesters such as poly(ethylene terephthalate); polyamides;polycarbonates; glassine paper; condenser paper; cellulose esters suchas cellulose acetate; fluorine polymers such as poly(vinylidenefluoride) or poly(tetrafluoroethylene-co-hexafluoropropylene);polyethers such as polyoxymethylene; polyacetals; polyolefins such aspolystyrene, polyethylene, polypropylene or methylpentene polymers; andpolyimides such as polyimide amides and polyetherimides. The supportgenerally has a thickness of from about 2 to about 30 μm.

[0071] The image-receiving element that is used with the dye-donorelement of the invention usually comprises a support having thereon adye image-receiving layer (from now on to be referred to as animage-receiving layer). The support may be a transparent film such as apoly(ether sulfone), a polyimide, a cellulose ester such as celluloseacetate, a poly(vinyl alcohol-co-acetal) or a poly(ethyleneterephthalate). The support for the image-receiving element may also bereflective such as baryta-coated paper, polyethylene-coated paper, whitepolyester (polyester with white pigment incorporated therein), an ivorypaper, a condenser paper or a synthetic paper such as DuPont Tyvek®.

[0072] The dye image-receiving layer may comprise, for example, apolycarbonate, a polyurethane, a polyester, poly(vinyl chloride),poly(styrene-co-acrylonitrile), polycaprolactone or mixtures thereof.The dye image-receiving layer may be present in any amount which iseffective for the intended purpose. In general, good results have beenobtained at a concentration of from about 1 to about 5 g/m².

[0073] As noted above, the dye donor elements of the invention are usedto form a dye-transfer image. Such a process comprises imagewise heatinga dye-donor element as described above and transferring a dye image toan image-receiving element to form the dye-transfer image. After the dyeimage is transferred, the protection layer is then transferred on top ofthe dye image.

[0074] The dye donor element of the invention may be used in sheet formor in a continuous roll or ribbon. If a continuous roll or ribbon isemployed, it may have only one dye or may have alternating areas ofother different dyes, such as sublimable cyan and/or magenta and/oryellow and/or black or other dyes. Such dyes are disclosed in U.S. Pat.Nos. 4,541,830; 4,698,651; 4,695,287; 4,701,439; 4,757,046; 4,743,582;4,769,360 and 4,753,922, the disclosures of which are herebyincorporated by reference. Thus, one-, two-, three- or four-colorelements (or higher numbers also) are included within the scope of theinvention.

[0075] In a preferred embodiment of the invention, the dye-donor elementcomprises a poly(ethylene terephthalate) support coated with sequentialrepeating areas of yellow, cyan and magenta dye, and the protectionlayer noted above, and the above process steps are sequentiallyperformed for each color to obtain a three-color dye-transfer image witha protection layer on top. Of course, when the process is only performedfor a single color, then a monochrome dye transfer image is obtained.

[0076] Thermal printing heads, which can be used to transfer dye fromthe dye-donor elements of the invention, are available commercially.There can be employed, for example, a Fujitsu Thermal Head FTP-040MCSOO1, a TDK Thermal Head LV5416 or a Rohm Thermal Head KE 2008-F3.

[0077] A thermal dye transfer assemblage of the invention comprises

[0078] (a) a dye-donor element as described above, and

[0079] (b) an image-receiving element as described above,

[0080] the dye-receiving element being in a superposed relationship withthe dye donor element so that the dye layer of the donor element is incontact with the dye image-receiving layer of the receiving element.

[0081] The above assemblage comprising these two elements may bepre-assembled as an integral unit when a monochrome image is to beobtained. This may be done by temporarily adhering the two elementstogether at their margins. After transfer, the image-receiving elementis then peeled apart to reveal the dye-transfer image.

[0082] When a three-color image is to be obtained, the above assemblageis formed on three occasions during the time when heat is applied by thethermal printing head. After the first dye is transferred, the elementsare peeled apart. A second dye-donor element (or another area of thedonor element with a different dye area) is then brought in registerwith the image-receiving element and the process is repeated. The thirdcolor is obtained in the same manner. Finally, the protection layer isapplied on top.

EXAMPLES

[0083] A. Receiver Element:

[0084] The image-receiving element that is used with the dye-donorelement of the invention usually comprises a support having thereon adye-receiving layer. The support may be a transparent film such as apoly(ether sulfone), a polyimide, a cellulose ester such as celluloseacetate, a poly(vinyl alcohol-co-acetal) or a poly(ethyleneterephthalate). The support for the dye-receiving element may also bereflective such as baryta-coated paper, polyethylene-coated paper, whitepolyester (polyester with white pigment incorporated therein), an ivorypaper, a condenser paper or a synthetic paper such as DuPont Tyvek®.

[0085] A dye image-receiving layer such as that found in Kodak Ektathermreceiver catalog #172-5514.

[0086] The dye image-receiving layer may comprise, for example, apolycarbonate, a polyurethane, a polyester, poly(vinyl chloride),poly(styrene-co-acrylonitrile), polycaprolactone or mixtures thereof.The dye image-receiving layer may be present in any amount which iseffective for the intended purpose. In general, good results have beenobtained at a concentration of from about 1 to about 5 g/m².

[0087] B. Donor Element:

[0088] Protective layer donor elements were prepared by coating on 6 μmPET (poly(ethylene terephthalate)) support:

[0089] On the back side of the element were coated the following layersin sequence:

[0090] 1) a subbing layer of 0.13 g/m² titanium butoxide (DuPont TyzorTBT®) from an 85% n-propyl acetate and 15% n-butyl alcohol solventmixture.

[0091] 2) a slipping layer containing an aminopropyl-dimethyl-terminatedpolydimethylsiloxane, PS513 (United Chemical Technologies, Bristol, Pa.)(0.011 g/m²), a poly(vinylacetal)(Sekisui KS-1) binder (0.38 g/m²),p-toluenesulfonic acid (0.0003 g/m²), candellila wax (0.022 g/m²) coatedfrom a solvent mixture of diethylketone, methanol and distilled water(88.7/9.0/2.3)

[0092] C. Protective Overlayer:

[0093] On the front side of the element was coated a transferableoverlayer of poly(vinyl acetal), KS-1, (Sekisui Co.), at a laydown of0.63 g/m², colloidal silica, IPA-ST (Nissan Chemical Co.), at a laydownof 0.462 g/m², and divinylbenzene beads, 4 micron average diameter,(Eastman Kodak Company), at a laydown of 0.011 g/m², coated from a 79%3-pentanone and 21% methanol mixture.

[0094] D. Test Conditions

[0095] Using Kodak Professional EKTATHERM XLS XTRALIFE Color Ribbon(Eastman Kodak Co. Catalog No. 807-6135) and a Kodak Model 8300 ThermalPrinter a Status A neutral density image with a maximum density of atleast 2.3 was printed on the receiver described above. The colorribbon-receiver assemblage was positioned on an 18 mm platen roller anda TDK thermal head (No. 3K0345) with a head load of 6.35 Kg was pressedagainst the platen roller. The TDK 3K0345 thermal print head has 2560independently addressable heaters with a resolution of 300 dots/inch andan average resistance of 3314 Ω. The imaging electronics were activatedwhen an initial print head temperature of 36.4° C. had been reached. Theassemblage was drawn between the printing head and platen roller at 16.9mm/sec. Coincidentally, the resistive elements in the thermal print headwere pulsed on for 58 μsec every 76 μsec. Printing maximum densityrequired 64 pulses “on” time per printed line of 5.0 msec. The voltagesupplied was 13.6 volts resulting in an instantaneous peak power ofapproximately 58.18×10−3 Watt/dot and the maximum total energy requiredto print Dmax was 0.216 mJoules/dot. The process is repeatedsequentially, yellow, magenta, cyan to obtain the desired neutral image.

[0096] Application of the transferable protective overlayer to thereceiver layer was done using a head voltage of 13.6 volts with anenable width of 72 microseconds. The size of the print is 2400×2680pixels.

[0097] Referring now to FIGS. 1-4, there will be described a method ofmaking a print in accordance with the present invention. In thepreferred method shown in FIG. 1, thermal print head 10 comprisingresistive elements 12 are used to transfer a protective overlayer 14from a donor element 16 to a print 18. Print 18 comprises an image layer26 on a support media 28. Print 18 of this invention is not limited to athermally transferred dye print, and can include any other method ofcreating a print, for example, inkjet, electrophotograhic, lithography,etc. The donor element 16 comprises a slipping layer (not shown) and asubbing layer (not shown) coated on a backside of a donor support 22. Onthe front side of the donor support is coated a donor overlayer 24.

[0098] As shown in FIG. 1, with the image layer 26 of print 18 incontact with the donor overlayer 24 of donor element 16, the donoroverlayer 24 can be transferred to print 18 by thermal print head 10. Asthermal print head 10 moves in direction “A” and resistive elements 12are selectively energized to different degrees, the donor overlayer 24is caused to separate from the donor support 22 and attach to the imagelayer 26 of print 18 in different thickness. The energy required totransfer the donor overlayer 24 in section “1 a” is greater than theenergy required to transfer the donor overlayer 24 in section “1 b”resulting in the thickness of the protective overlayer 14 in section “1a” to be greater than the thickness of the protective overlayer 14 insection “1 b”. In this embodiment, protective overlayer 14 is acontinuous layer over the entire surface area of image layer 26, and thethickness of protective overlayer 14 at any given point is limited tothe thickness defined in either section “1A” or “1B”.

[0099] Shown in FIG. 2 is an alternate embodiment of the currentinvention. With the image layer 26 of print 18 in contact with the donoroverlayer 24 of donor element 16, the donor overlayer 24 can betransferred to the print 18 by thermal print head 10. As thermal printhead 10 moves in direction “A” and resistive elements 12 are selectivelyenergized, the donor overlayer 24 is caused to separate from the donorsupport 22 and attach to the image layer 26 of print 18 in the selectiveareas. The thermal print head 10 is energized as it moves across section“2 a”, and de-energized as it moves across section “2 b”. In thisembodiment, protective overlayer 14 is not a continuous layer over theentire surface area of image layer 26, and the thickness of protectiveoverlayer 14 at any given point is limited to the thickness defined ineither section “2 a” or “2 b”.

[0100] Shown in FIG. 3 is another alternate embodiment of the currentinvention. With the image layer 26 of print 18 in contact with the donoroverlayer 24 of donor element 16, the donor overlayer 24 can betransferred to the print 18 by thermal print head 10. As thermal printhead 10 moves in direction “A” and resistive elements 12 arede-energized or selectively energized to different degrees, the donoroverlayer 24 is caused to separate from the donor support 22 and attachto the image layer 26 of print 18 in different thickness. The energyrequired to transfer the donor overlayer 24 in section “3 a” is greaterthan the energy required to transfer the donor overlayer 24 in section“3 b”. In section “3 c”, the thermal print head 10 is de-energized. Theresulting in the thickness of the protective overlayer 14 in section “3a” is greater than the thickness of the protective overlayer 14 insection “3 b”, and there is an absence of protective overlayer insection “3 c”. In this embodiment, the thickness of protective overlayer14 at any given point is limited to the thickness defined in eithersection “3 a”, “3 b”, or “3 c”.

[0101] Referring now to FIG. 4, there is shown a product made inaccordance with the preferred method of the current invention. For thepurpose of discussion, the product shown is a label 30. On the imagelayer 26 of label 30 is an image 32, and the protective overlayer 14 oflabel 30 comprises information-bearing indicia 34. Theinformation-bearing indicia 34 shown is in the form of a bar code. Theenergy required to transfer the protective overlayer 14 in section “4 a”is greater than the energy required to transfer the protective overlayer14 in section “4 b” resulting in the thickness of the protectiveoverlayer 14 in section “4 a” to be greater than the thickness of theprotective overlayer 14 in section “4 b”. The resulting thicknessdifferential defines indicia. It should be noted that theinformation-bearing indicia is not limited to a bar code, but can takeany form, for example Braille, text, symbols, etc. As shown in FIG. 4,the location of the information bearing indicia 34 overlap the image 32on print 18. Protective overlayer 14 is substantially transparent, andthe incorporated information-bearing indicia 34 in protective overlayer14 does not add any human detectable opacity. Therefore, image 32 isviewable through protective overlayer 14 and information-bearing indicia34.

[0102] Shown in FIG. 5 is a product 36 onto which label 30 is applied.Image 32 on label 30 is visible to the viewer and human readable. Theinformation-bearing indicia 34 is machine-readable, therefore,substantially invisible to the viewer.

[0103] Next will be described several methods for reading the dataembedded in the protective overlayer 14. The methods described are formsof surface profilometry. It should be noted that we are not limited tothe methods described herein, and that other methods reading the data bysurface profilometry may be applied.

[0104]FIG. 6A shows a topographic representation of information-bearingindicia 34 taken along a multiple traces using a Gould Microtopographerstylus instrument. This technique for measuring/mapping the physicalsurface contour is done with a contact instrument using a diamond styluswith a light load (50 mg). The diamond stylus tip has a 2.5-micronradius with a 90 degree included angle. Multiple traces are required tomap the surface of an area. A single trace as shown in FIG. 6B islimited to surface contact area of the stylus tip. In this example, itshould be noted that measurements could be read directly from the graphto determine the physical size relationship of the surfacecharacteristics. The stylus indexes after each trace, and the system iscalibrated to specimen # 2071 traceable to the National Institute ofStandards and Technology (NIST). In this example, the information shownin the topographic representation can be translated into bar codeinformation by converting the peaks to bars and the valleys to spaces.

[0105]FIGS. 7A and 7B show a topographic representation ofinformation-bearing indicia 34 mapped using a Zygo NewView 5000. Thistechnique for measuring/mapping the surface is done using a non-contact3D optical profiler, having sub-nanometer z resolution, and is capableof mapping areas up to 17.5 mm. FIG. 7A is an oblique view of the totalmapped area, while FIG. 7B is an elevation view showing the surfaceprofile.

[0106]FIG. 8A represents a means for reading the information containedin the code within the overcoat using direct illumination 40 and anoptical detector 42. The preferred illumination source for thisapplication is a collimated visible laser beam in the 600-700 nmwavelength range, as is commonly found within both handheld andpoint-of-sale bar code readers, or alternatively, a focussed spot oflight from a non-coherent light source such as an incandescent or arclamp. This type of reader detects the change in surface characteristics.In this method, an illuminating beam 44 is placed at a preferredincident angle 46 while the optical detector 42 is held at a suitabledetection angle 48 such as to maximize the response of the detector tothe modulation of a reflected light 50 beam as the target area isscanned. The preferred incident and detection angles will depend uponthe actual materials used and degree of scattering from the encodedareas. Scanning is accomplished either by relative motion of the readerand code symbol or by opto-mechanical deflection of the incident beamtypically using a oscillating or rotating mirror as is common practicein bar code readers.

[0107]FIG. 8B represents a means for reading the information containedin the code within the overcoat using direct illumination 40 and opticaldetection 42 with addition of a pre-polarizer 52 and, subsequently, apolarization analyzer 54. The preferred illumination source for thisapplication is a collimated visible laser beam in the 600-700 nmwavelength range, as is commonly found within both handheld andpoint-of-sale bar code readers. Alternatively, a focussed spot of lightfrom an non-coherent light source, such as, an incandescent or arc lamp,the output of which has been polarized by a polarizing element may beused (not shown).

[0108] In this method, the polarized illuminating beam 44 is placed at apreferred incident angle 46 while the detector 42 is held at a suitabledetection angle 48 such as to maximize the response of the detector tothe modulation of the reflected light beam as the target area isscanned. The polarization analyzer 54 is used as an analyzer to enablethe discrimination between light whose polarization has been altered bythe encodement from light whose polarization has not been effected. Thepreferred incident, detection, and polarization angles will depend uponthe actual materials used and degree of de-polarization of the incidentlight in the encoded areas. Scanning is accomplished either by relativemotion of the reader and code symbol or by opto-mechanical deflection ofthe incident beam typically using a galvanometer or rotating mirror asis common practice in bar code readers.

[0109] Common to both FIGS. 8A and 8B, as print 18 moves in thedirection of arrow 56, illuminating beam 44 illuminatesinformation-bearing indicia 34 along a single trace in a linear fashion.In order to illuminate a larger area of the information-bearing indicia34, multiple traces need to be taken in a step-wise function.

[0110] In the embodiment where the indicia 34 is a machine-readable codeXX printed in a bar code format. One example of the bar code XX is theUniversal Product Code (UPC). Other examples of standard ID or linearbar codes are “2 of 5” and “3 of 9”. The previously mentioned bar codesare understood by those skilled in the art. These bar codes are read byscanning in a direction that is perpendicular to the bars and spaces viaa bar code reader, such as, those commonly used in grocery storecheckouts. However, it is to be understood that any suitablemachine-readable code may be used that is currently available or maybecome available, for example, but not by way of limitation, a bar code.

[0111] In another embodiment where the indicia 34 is a readable patternsuch as Braille. The incident-beam laser scans the topographicrepresentation of information-bearing indicia, and via reflected orabsorbed light records the topographic map in memory. The topographicmap is then compared by running through a pattern recognition algorithmand matched known patterns for Braille letters. The pattern, forexample, but not by way of limitation, Braille.

[0112] In yet another embodiment where the indicia 34 represents abinomial code, the incident-beam laser scans the code and it is decodedvia a binomial code look up table.

[0113] Referring now to FIG. 9, there is shown an alternate product madein accordance with the preferred method of the current invention. Forthe purpose of discussion, the product shown is a label 30. FIG. 9 is anexploded view of a print having identical indicia printed on the imagelayer 26 and in a protective overlayer 14. As shown in FIG. 9, therepresented indicia is a 1-Dimensional (1-D) bar code. It should benoted that the indicia is not limited to a bar code, but can take anyform, for example, Braille, text, symbols, 2-Dimensional code, etc.Image 32 and protective overlayer 14 of label 30 compriseinformation-bearing indicia 34. As shown in FIG. 9, the informationbearing indicia 34 and image 32 comprise the same information, and thelocation of the information bearing indicia 34 exactly overlap the image32 on print 18.

[0114] The reflective characteristics of the protective overlayer 14 arealtered in the area of the information-bearing indicia 34. In addition,the reflective characteristics of the protective overlayer 14 arealtered in the area that is in register with image 32. By default, thereflective characteristics of image 32 are such that light is absorbedin printed areas and reflected in non-printed area. By changing thereflective characteristics of the protective overlayer 14 in registerwith the reflective characteristics of image 32, the readability of theindicia on label 30 is enhanced when read with an incident-beam laserscanner.

[0115] FIGS. 10-13 show various arrangements of indicia encoded into theprotective overlayer 14. Specifically, FIG. 10 shows a minimum thicknessof the protective overlayer applied over the entire surface of print 18,and a second greater thickness of the protective overlayer applied tothe surface of print 18 where image 32 is located. The differencebetween the minimum and second greater thickness is such that adetectable difference can be discerned. FIG. 11 shows a maximumthickness of the protective overlayer applied to the surface of print 18where image 32 is located, and an absence of the protective overlayerwhere there is an absence of an image. FIG. 12 shows a minimum thicknessof the protective overlayer applied over the entire surface of print 18,and a maximum thickness of the protective overlayer applied to thesurface of print 18 where there is an absence of an image. FIG. 13 showsa maximum thickness of the protective overlayer applied to the surfaceof print 18 where there is an absence of an image, and a maximumthickness of the protective overlayer applied to the surface of print 18where image 32 is located.

[0116] A test was done to determine the readability of a bar code madein accordance with the present invention as shown in FIG. 9. Two samplebar codes were prepared. Sample “A” is a process black bar code printedusing cyan, magenta, and yellow dyes on a white receiver. Sample “B” isa process black bar code printed using cyan, magenta, and yellow dyes ona white receiver plus image-wise application of the protectiveoverlayer. Image-wise in this context meaning that the protectiveoverlayer is applied only in the black areas of the bar code. Bothsamples were read using a 660-nm wavelength bar code reader. On a scaleof 0-4.0, with 4.0 being the highest rating, sample “A” scored a ratingof 3.5, and sample “B” scored a rating of 3.8. A 10% rating increase wasrealized when the protective overlayer was applied in an image-wisefashion.

[0117] In addition, it was noted that there is a difference in thereadability of thermally printed bar codes depending on the orientationof the bar code to the direction of print. The difference was morenotable when a protective overlayer was applied. Two sample bar codeswere prepared. Sample “AA” is a process black bar code printed usingcyan, magenta, and yellow dyes on a white receiver, an image-wiseapplication of the protective overlayer, and where the orientation ofthe bars is 90° to the direction of print. Sample “BB” is a processblack bar code printed using cyan, magenta, and yellow dyes on a whitereceiver, an image-wise application of the protective overlayer, andwhere the orientation of the bars is 0° to the direction of print. Bothsamples were read using a 660-nm wavelength bar code reader. On a scaleof 0-4.0, with 4.0 being the highest rating, sample “AA” scored a ratingof 3.0 and sample “BB” scored a rating of 3.8. A 25% rating increase wasrealized when the orientation of the bar code was 0° to the direction ofprint.

[0118] The entire contents of the patents and other publicationsreferred to in this specification are incorporated herein by reference.

[0119] It should be noted that the image-bearing print portion of thisinvention is not limited to a thermally transferred dye print and caninclude any other method of creating a print, for example, inkjet,electrophotograhic, lithography, etc.

[0120] The invention has been described in detail with particularreference to certain preferred embodiments thereof, but it will beunderstood that variations and modifications can be effected within thescope of the invention.

Parts List

[0121]10 print head

[0122]12 resistive elements

[0123]14 protective overlayer

[0124]16 donor element

[0125]18 print

[0126]22 donor support

[0127]24 donor overlayer

[0128]26 image layer

[0129]28 support media

[0130]30 label

[0131]32 image

[0132]34 indicia

[0133]36 product

[0134]42 optical detection

[0135]44 illuminating beam

[0136]46 incident angle

[0137]48 detection angle

[0138]50 reflective light

[0139]52 pre-polarizer

[0140]54 polarization analyzer

[0141]56 arrow

What is claimed is:
 1. A media comprising: a) an image-receiving layeron which an image may be formed; and b) a protective overlayer providedover said image-receiving layer, said protective overlayer havingmachine-readable indicia formed thereon.
 2. A media comprising: a) animage-receiving layer on which an image may be formed using a thermalhead; and b) a protective overlayer provided over said image-receivinglayer, said protective overlayer having machine-readable indicia formedthereon.
 3. The media of claim 2 wherein said indicia being transparentso as to allow viewing of an image provided on said image-receivinglayer.
 4. The media of claim 2 wherein said protective overlayercomprises an IR absorbing dye.
 5. The media of claim 2 furthercomprising an adhesive layer for securing to an item.
 6. A mediacomprising: a) a 1^(st) machine-readable indicia in an image layer onsaid media; and b) a 2^(nd) machine-readable indicia in a protectiveoverlayer that is identical in content to, and in register with said1^(st) machine-readable indicia in said image layer.
 7. A labelcomprising: a) a image-receiving layer on which an image may be formedusing a thermal head; and b) a protective overlayer provided over saidimage-receiving layer, said protective overlayer having machine-readableindicia formed thereon.